Sap-collecting systems for maple trees consist of a network of connectors and conductors that operate under vacuum conditions to suck sap from the trees and direct it to a central sap-processing unit. These conductors consist of small conduits connecting the trees to tubular members of larger diameter (called mains) bringing the sap to the central unit. When the sun goes down and the temperature lowers, the sap that remains in the mains freezes. It is only when the temperature rises again above 32.degree. F. that the sap will defreeze and the sap collecting and conducting process will carry on.
In order to obtain as much sap as possible, conduits of dark color (black) are used so that sun rays may be absorbed early in the morning to assist in the defreezing process of sap contained in the mains. The earlier the sap will start to flow in the network, the larger the quantity of sap collected.
However, one main disadvantage of black conduits is that sap temperature can rise up to 70.degree. F. with high noon sun rays. At 70.degree. F. temperature, bacterial growth is favored to an important degree, causing the resulting syrop to be darker and of a lesser quality than that desired. On the other hand, if light-shaded colored (white) conduits are used, the sap defreezing process may be delayed up to two hours comparatively to black conductors. Still, because the sap temperature is maintained lower than with black conduits, the sap collected, although of a small quantity, is of a higher quality.
There are, therefore, advantages and disadvantages associated with both colors of conductors.